Passenger detection device of automobile

ABSTRACT

A passenger detection device of an automobile that can easily detect a passenger&#39;s weight is provided. The passenger detection device of an automobile includes: a weight sensor module for detecting a first voltage difference value and a first temperature at a first point of a seat; and a smart sensor module for detecting a second voltage difference value and a second temperature at a second point of the seat, calculating a final weight of the first and second voltage difference values using the first and second temperatures, and detecting a passenger by comparing the final weight and a setting reference.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Application No. 2008-0065011, filed on Jul. 4, 2008 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a passenger detection device of an automobile that can easily detect a passenger's weight.

2. Description of the Related Art

In general, an automobile is completed by assembling and mounting about 3,000 parts consisting of design parts and electrical parts of the inside and the outside of an automobile room such as an interior component, a dashboard, a seat, window glass, and an electrical component, and units such as an engine, a transmission, and an axle in an automobile body and performing wiring and piping operations and is launched as a product after a quality check.

Further, in order to improve performance of the automobile, the automobile depends on the control of an advanced electronic device in many portions.

Particularly, by improving performance of an engine using various sensors, optimum engine efficiency is obtained and thus reliability of the automobile is improved.

Further, for driver convenience, safety of a driver and a passenger as well as actual engine driving, by detecting the passenger's weight and classifying an adult and a child using an advanced electronic device, the passenger's safety can be improved.

Therefore, nowadays, in order to secure safety of the passenger and the driver, an apparatus for detecting the passenger's weight has been developed.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to solve the above problems, and the present invention provides a passenger detection device of an automobile that can easily detect a passenger's weight.

According to an aspect of the present invention, there is provided a passenger detection device of an automobile including: a weight sensor module for detecting a first voltage difference value and a first temperature at a first point of a seat; and a smart sensor module for detecting a second voltage difference value and a second temperature at a second point of the seat, calculating a final weight according to preset temperature correction values corresponding to the first and second temperatures and the first and second voltage difference values, and detecting a passenger by comparing the final weight and a setting reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings, which are given by illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a view schematically illustrating an inflation state of an air bag of an automobile according to an exemplary embodiment of the present invention;

FIG. 2 is a block diagram illustrating a configuration of a passenger detection device of an automobile according to an exemplary embodiment of the present invention; and

FIG. 3 is a circuit diagram of the passenger detection device of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, exemplary embodiments of a passenger detection device of an automobile according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a view schematically illustrating an inflation state of an air bag of an automobile according to an exemplary embodiment of the present invention.

When a collision accident occurs in an automobile, in order to safely protect a passenger using a cushion operation, an air bag 10 is installed at the front or the side of the automobile.

Referring to FIG. 1, the air bag 10 is classified into an air bag (DAB) for a driver's seat installed at a steering wheel in order to protect the front of a driver seated in the driver's seat and an air bag (PAB) for a passenger' seat installed at an instrument panel in order to protect the front of a passenger seated in the passenger' seat.

Further, nowadays, in order to protect a passenger from a side collision as well as a front collision, a side air bag installed within the back of a seat, or a door trim of the automobile, a curtain air bag mounted in a roof rail and to be inflated in a curtain form between the passenger and a side window, and a side protection air bag of an inflatable tubular structure (ITS) mounted within a head liner of the upside of a front seat door are mounted in the automobile.

Because the air bag 10 instantaneously inflates by inflation gas of a high pressure, excessive inflation of the air bag 10 may injure a passenger. By inflating the air bag 10 with an appropriate inflation pressure according to a passenger type based on a body condition, in order to protect the passengers of various body conditions, the air bag 10 is controlled by a passenger detection device (not shown) including a weight sensor and a smart sensor for detecting a passenger's weight.

FIG. 2 is a block diagram illustrating a configuration of a passenger detection device of an automobile according to an exemplary embodiment of the present invention.

Referring to FIG. 2, a passenger detection device according to the present exemplary embodiment includes a weight sensor module 40 and a smart sensor module 50.

The weight sensor module 40 and the smart sensor module 50 are positioned at first and second points, respectively of a lower part of a seat (not shown). For example, the weight sensor module 40 may be positioned at the center of the left side of the lower part of the seat, and the smart sensor module 50 may be positioned at the center of the right side of the lower part of the seat.

The weight sensor module 40 detects a first voltage difference value and a first temperature at the first point at which the passenger is seated and transfers the first voltage difference value and the first temperature to the smart sensor module 50.

The weight sensor module 40 includes a first sensing unit 44 for detecting first and second voltage values and the first temperature at the first point and a first level amplification unit 48 for outputting a first voltage difference value, which is a difference value between the first and second voltage values and correcting a zero point of the first voltage difference value.

Further, the weight sensor module 40 provides the first voltage difference value to the smart sensor module 50. Therefore, the smart sensor module 50 calculates a first weight value with reference to the first voltage difference value and a preset weight calculation value, temperature correction value, and resistance error correction value. The weight calculation value is a value for calculating a voltage difference value to a weight value, the temperature correction value is a value for correcting a semiconductor gauge output value that is different according to a temperature, and the resistance error correction value is a value for correcting an error of a resistance value included in the semiconductor gauge. The smart sensor module 50 acquires a second voltage difference value, calculates a second weight value with reference to the second voltage difference value and the preset weight calculation value, temperature correction value, and resistance error correction value, and calculates a final weight by adding the first weight value and the second weight value.

The first sensing unit 44 includes a first semiconductor gauge 41 for detecting the first and second voltage values and a first temperature detection unit 43 for detecting the first temperature at the inside or the outside of the first semiconductor gauge 41.

In the first semiconductor gauge 41, a plurality of semiconductor resistors (not shown) having varying resistance values are connected in a bridge form.

The first semiconductor gauge 41 outputs the first and second voltage values at the first point.

Further, the first temperature detection unit 43 detects a temperature of the first semiconductor gauge 41 at any time and outputs the first temperature. That is, as the first semiconductor gauge 41 sensitively reacts to a heat, the first and second voltage values are affected by a temperature, and thus the first temperature detection unit 43 detects the first temperature in order to compensate a temperature.

The first level amplification unit 48 includes a first amplification unit 45 for amplifying and outputting a first voltage difference value, which is a difference value between the first and second voltage values and a first correction unit 47 for correcting and outputting a zero point of the first voltage difference value.

The first amplification unit 45 is preferably an operating amplifier (op-amp) and outputs the first voltage difference value in which the first and second voltage values are supplied and amplified to an inversion terminal and a non-inversion terminal, respectively.

The first correction unit 47 corrects a zero point of the first voltage difference value using the first voltage difference value and a first zero point signal supplied from the smart sensor module 50. In this case, when a voltage value calculated between two of a plurality of semiconductor resistors included in the semiconductor gauge is different from a reference voltage value, zero point correction is performed in order to correct the voltage value.

The smart sensor module 50 includes a second sensing unit 54 for detecting third and fourth voltage values and the second temperature at the second point, a second level amplification unit 58 for acquiring a second voltage difference value, which is a difference value between the third and four voltage values and correcting a zero point of the second voltage difference value, and a controller 59 for calculating a final weight according to the first and second voltage difference values, detecting a passenger by comparing the final weight and a setting reference, and controlling the first and second level amplification units 48 and 58 in order to correct a zero point of the first and second voltage difference values.

That is, the smart sensor module 50 acquires a second voltage difference value, calculates a second weight value with reference to the second voltage difference value and the preset weight calculation value, temperature correction value, and resistance error correction value, and calculates a final weight by adding the second weight value and the first weight value calculated by the first voltage difference value received from the weight sensor module 40.

The second sensing unit 54 includes a second semiconductor gauge 51 for detecting the third and fourth voltage values and a second temperature detection unit 53 for detecting the second temperature at the inside or the outside of the second semiconductor gauge 51.

In the second semiconductor gauge 51, a plurality of semiconductor resistors (not shown) having varying resistance values are connected in a bridge form.

The second semiconductor gauge 51 outputs the third and fourth voltage values at the second point.

Further, the second temperature detection unit 53 detects a temperature of the second semiconductor gauge 51 at any time and outputs the second temperature. That is, as the second semiconductor gauge 51 sensitively reacts to a heat, the third and fourth voltage values are affected by a temperature, and thus the second temperature detection unit 53 detects the second temperature in order to compensate a temperature.

The second level amplification unit 58 includes a second amplification unit 55 for amplifying and outputting a second voltage difference value, which is a difference value between the third and fourth voltage values and a second correction unit 57 for correcting and outputting a zero point of the second voltage difference value.

The second amplification unit 55 is preferably an operating amplifier (op-amp) and outputs the second voltage difference value in which the third and fourth voltage values are supplied and amplified to an inversion terminal and a non-inversion terminal, respectively.

The second correction unit 57 corrects a zero point of the second voltage difference value using the second voltage difference value and a second zero point signal supplied from the controller 59.

The controller 59 includes a calculation unit 59_1 for calculating the final weight according to a preset temperature correction value corresponding to the first and second temperature, a zero point adjustment unit 59_2 for supplying the first and second zero point signals to the first and second level amplification units 48 and 58, and a determination unit 59_3 for determining whether the passenger is detected by comparing the final weight with the setting reference, and a power supply unit 59_4 for supplying power to the first and second sensing units 44 and 54.

The calculation unit 59_1 has a lookup table in which a correction value for a temperature change amount based on a reference temperature, compensates the first and second temperatures through the lookup table, and thus calculates a final weight.

The zero point adjustment unit 59_2 outputs the first and second zero point signals to the first and second correction units 47 and 57 in order to correct zero points of the first and second voltage difference values.

The determination unit 59_3 determines, if the final weight satisfies the setting reference, that the passenger is detected and determines, if the final weight does not satisfy the setting reference, that the passenger is not detected.

If the passenger is detected, the determination unit 59_3 determines whether the passenger is an adult or an infant based on the setting reference and transfers information about the passenger to a control unit for adjusting an air pressure of an air bag when the air bag is inflated according to the determination.

That is, when the final weight satisfies a passenger detection minimum value with reference to a determination reference database, the determination unit 59_3 determines that the passenger is detected and in this case, if the final weight is a preset adult threshold value or more referring again to the determination reference database, the determination unit 59_3 determines that the passenger is an adult, and if the final weight is less than a preset adult threshold value referring again to the determination reference database, the determination unit 59_3 determines that the passenger is an infant.

FIG. 3 is a circuit diagram of the passenger detection device of FIG. 2.

Referring to FIG. 3, a passenger detection device according to the present exemplary embodiment includes a weight sensor unit 40 and a smart sensor module 50.

The weight sensor module 40 includes a first sensing unit 44 and a first level amplification unit 48.

The first sensing unit 44 includes a first semiconductor gauge 41 in which first, second, third, and fourth semiconductor resistors R1, R2, R3, and R4 having varying resistance values are connected in a bridge form and a first temperature detection unit 43 for detecting a first temperature at the inside and the outside of the first semiconductor gauge 41.

In the first semiconductor gauge 41, power of the power supply unit 59_4 included in the smart sensor module 50 is supplied to a first contact point A1 at which the first and third semiconductor resistors R1 and R3 are connected, a first voltage value is output to a second contact point A2 at which the first and second semiconductor resistors R1 and R2 are connected, and a second voltage value is output to a third contact point A3 at which the third and fourth semiconductor resistors R3 and R4 are connected, and a fourth contact point A4 at which the second and fourth semiconductor resistors R2 and R4 are connected is connected to the ground.

The first voltage value is a voltage output at the second contact point A2, i.e. between the first and second semiconductor resistors R1 and R2, and the second voltage value is a voltage output at the third contact point A3, i.e. between the third and fourth semiconductor resistors R3 and R4.

Further, the first temperature detection unit 43 detects the first temperature of the first semiconductor gauge 41 and transfers the first temperature to the smart sensor module 50.

The first level amplification unit 48 includes a first amplification unit 45 for amplifying and outputting a difference value between the first and second voltage values and a first correction unit 47 for correcting a zero point of the first voltage difference value.

In the first amplification unit 45, the first voltage value is supplies to a non-inversion terminal (−) and the second voltage value is supplied to an inversion terminal (+), and the first amplification unit 45 amplifies and outputs a difference value between the first and second voltage values.

The first correction unit 47 receives the first voltage difference value and the first zero point signal, corrects a zero point of the first voltage difference value based on the first zero point signal, and transfers the corrected zero point to the smart sensor module 50.

The smart sensor module 50 includes a second sensing unit 54, a second level amplification unit 58, and a controller 59.

The second sensing unit 54 includes a second semiconductor gauge 51 in which fifth, sixth, seventh, and eighth semiconductor resistors R5, R6, R7, and R8 having varying resistance values are connected in a bridge form and a second temperature detection unit 53 for detecting a second temperature at the inside and the outside of the second semiconductor gauge 51.

In the second semiconductor gauge 51, power of the power supply unit 59_4 included in the smart sensor module 50 is supplied to a fifth contact point A5 at which the fifth and seventh semiconductor resistors R5 and R7 are connected, a third voltage value is output to a sixth contact point A6 at which the fifth and sixth semiconductor resistors R5 and R6 are connected, and a fourth voltage value is output to a seventh contact point A7 at which the seventh and eighth semiconductor resistors R7 and R8 are connected, and an eighth contact point A8 at which the sixth and eighth semiconductor resistors R6 and R8 are connected is connected to the ground.

The third voltage value is a voltage output at the sixth contact point A6, i.e. between the fifth and sixth semiconductor resistors R5 and R6, and the fourth voltage value is a voltage output at the seventh contact point A7, i.e. between the seventh and eighth semiconductor resistors R7 and R8.

Further, the second temperature detection unit 53 detects the second temperature of the second semiconductor gauge 51 and transfers the second temperature to the controller 59.

The second level amplification unit 58 includes a second amplification unit 55 for amplifying and outputting a difference value between the third and fourth voltage values and a second correction unit 57 for correcting a zero point of the second voltage difference value.

In the second amplification unit 55, the third voltage value is supplied to a non-inversion terminal (−) and the fourth voltage value is supplied to an inversion terminal (+), and the second amplification unit 55 amplifies and outputs a difference value between the third and fourth voltage values.

The second correction unit 57 receives the second voltage difference value and the second zero point signal, corrects a zero point of the second voltage difference value based on the second zero point signal, and transfers the zero point to the controller 59.

The first and second semiconductor gauges 41 and 51 are formed in a chip form, and the first and second temperature detection units 43 and 53 can detect a temperature change in a chip surface of each of the first and second semiconductor gauges 41 and 51.

As shown in FIG. 2, the controller 59 includes a calculation unit 59_1, a zero point adjustment unit 59_2, and a determination unit 59_3.

The calculation unit 59_1 has a lookup table in which a correction value for temperature change amount based on a reference temperature, compensates temperature through the lookup table, and calculates a final weight.

The zero point adjustment unit 59_2 outputs the first and second zero point signals to the first and second correction units 47 and 57 in order to correct zero points of the first and second voltage difference values.

The determination unit 59_3 determines, if the final weight satisfies the setting reference, that the passenger is detected and determines, if the final weight does not satisfy the setting reference, that the passenger is not detected.

As described above, a passenger detection device of an automobile can easily detect a passenger's weight and includes a smart sensor module including a controller for calculating a final weight of the passenger, determining whether a passenger is detected according to a setting reference, and classifying the passenger according to the setting reference, and thus calculates a final weight in which a temperature error is corrected through a temperature of first and second semiconductor gauges included in a weight sensor module and the smart sensor module, so that the quantity of circuit components can be reduced, and thus a cost can be reduced and a process can be improved.

The embodiment of the invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

1-10. (canceled)
 11. A passenger detection device of an automobile, comprising: a weight sensor module for detecting a first voltage difference value and a first temperature at a first point of a seat; and a smart sensor module for detecting a second voltage difference value and a second temperature at a second point of the seat, calculating a final weight according to preset temperature correction values corresponding to the first and second temperatures and the first and second voltage difference values, and detecting a passenger by comparing the final weight and a reference setting.
 12. The passenger detection device of claim 11, wherein the weight sensor module comprises: a first sensing unit for detecting first and second voltage values and the first temperature at the first point; and a first level amplification unit for outputting the first voltage difference value, which is a difference value between the first and second voltage values, and correcting a zero point of the first voltage difference value.
 13. The passenger detection device of claim 12, wherein the first level amplification unit comprises: a first amplification unit for amplifying the difference value between the first and second voltage values and outputting the first voltage difference value; and a first correction unit for correcting and outputting a zero point of the first voltage difference value.
 14. The passenger detection device of claim 12, wherein the first sensing unit comprises: a first semiconductor gauge for detecting the first and second voltage values; and a first temperature detection unit for detecting the first temperature at one of the inside and the outside of the first semiconductor gauge.
 15. The passenger detection device of claim 14, wherein in the first semiconductor gauge, first, second, third, and fourth semiconductor resistors having varying resistance values are connected in a bridge form, and power is supplied to a first contact point at which the first and third semiconductor resistors are connected, the first voltage value is output to a second contact point at which the first and second semiconductor resistors are connected, the second voltage value is output to a third contact point at which the third and fourth semiconductor resistors are connected, and a fourth contact point at which the second and fourth semiconductor resistors are connected is connected to the ground.
 16. The passenger detection device of claim 11, wherein the smart sensor module comprises: a second sensing unit for detecting third and fourth voltage values and the second temperature at the second point; a second level amplification unit for outputting the second voltage difference value, which is a difference value between the third and fourth voltage values and correcting a zero point of the second voltage difference value; and a controller for calculating a final weight based on the first and second voltage difference values, detecting a passenger by comparing the final weight and the reference setting, and supplying first and second zero point signals to the first and second level amplification units, respectively, in order to correct zero points of the first and second voltage difference values.
 17. The passenger detection device of claim 16, wherein the second level amplification unit comprises: a second amplification unit for amplifying and outputting the second voltage difference value, which is a difference value between the third and fourth voltage values; and a second correction unit for correcting and outputting the zero point of the second voltage difference value.
 18. The passenger detection device of claim 16, wherein the second sensing unit comprises: a second semiconductor gauge for detecting the third and fourth voltage values; and a second temperature detection unit for detecting the second temperature at one of the inside and the outside of the second semiconductor gauge.
 19. The passenger detection device of claim 18, wherein in the second semiconductor gauge, fifth, sixth, seventh, and eighth semiconductor resistors having varying resistance values are connected in a bridge form, and power is supplied to a fifth contact point at which the fifth and seventh semiconductor resistors are connected, the third voltage value is output to a sixth contact point at which the fifth and sixth semiconductor resistors are connected, the fourth voltage value is output to a seventh contact point at which the seventh and eighth semiconductor resistors are connected, and an eighth contact point at which the sixth and eighth semiconductor resistors are connected is connected to the ground.
 20. The passenger detection device of claim 16, wherein the controller comprises: a calculation unit for calculating the final weight through a lookup table having at least one temperature correction value, which is a value for compensating temperature change amount based on a reference temperature; a zero point adjustment unit for supplying the first and second zero point signals corresponding to the first and second voltage difference values to the first and second level amplication units; and a determination unit for comparing the final weight with the reference setting and determining whether the passenger is detected. 